This invention is directed to ink compositions resistant to solvent evaporation, particularly for use in permanent marker pens and other marker devices, such as retractable permanent marker pens.
Current permanent marker pens employ inks made with a solvent base system. These markers have at least one end that forms the marking or writing tip, also known as the nib. The solvent from the ink will evaporate upon usage, thus causing the marker pen to “dry out”. To avoid solvent evaporation, traditional permanent marker pens require a tightly fitted cap over the nib portion of the marker pen to prevent the marker pen from drying out.
One performance indicator of a marker pen is the cap-off performance which measures the markers ability to mark with ink after the cap has been off for a particular amount of time. Traditionally, after less than 2 (two) hours, the ink will dry up, thus yielding a low cap-off performance. Due to the need for a cap to prevent dry-out, it is difficult to create a retractable permanent marker pen that does not require a cap.